Do Psychedelic Experiences Present a Challenge to Naturalism?

Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Chemical Collective or any associated parties.

Our psychedelic experiences often involve things that seem out of line with everyday reality. Sometimes, what we experience seems out of line with what is known by science. This potential conflict goes deeper than disagreeing with scientific knowledge or even the experience-reality distinction. It cuts to the core of the philosophy that underpins the idea of science as a way of learning about the universe.

What is Naturalism?

Naturalism is the idea that only things that are part of nature, in the broadest sense of the word, exist. Put another way, if something exists, it must be due to natural causes, not supernatural intervention, and follow laws of nature. By this definition, things like rocks, trees, humans, and all the things we’ve created are natural in that they arose from the natural world and are governed by things like the laws of physics. Things that are beyond natural causes, like a divine being that creates natural laws but is not subject to any of them, are not part of nature and cannot exist.  

Historically, the philosophy of naturalism is associated with the rise of the scientific worldview, though there’s debate on whether one caused the other. Whatever the case, many philosophers argue that naturalism is the implicit philosophy of scientists and science.

There are varieties of this naturalism, which turn out to be highly relevant later. But since we’re talking about psychedelics, it’s worth looking at a strict form of it, such as the one supported by Chris Letheby in his 2021 book, Philosophy of Psychedelics. By Letheby’s definition, naturalism is as described above. But, he also takes this to mean that things like ‘disembodied minds’ and ‘any transcendent forms of consciousness not dependent on any specific brain or cognitive system’ are impossible (2021, p. 28). For Letheby, physicalism about the mind (p. 38), in that minds can only arise from physical brains or something like them, is acceptable, and cosmic consciousness is not (p. 30). Nor does he seem particularly impressed with panpsychism. By Letheby’s standards, the modern scientific worldview and naturalism are largely synonymous, especially regarding consciousness.

Are Psychedelic Experiences Compatible with Naturalism?

As with a lot of philosophical questions, the answer to this one is ‘it depends.’

What we take psychedelic experiences to mean and how we interpret them play a huge role in whether they present a problem for strict naturalism.

For example, I once took enough Salvia divinorum extract (back when it was legal in Australia) to have a full ‘breakthrough’ and experienced being outside of time. If I interpret this as an illusion, that the mental imagery was purely due to the chemical effects of Salvinorin A on the relevant receptors, and leave it at that, that’s completely consistent with even very strict forms of naturalism. My experience is still consistent with naturalism if what I experienced helped me understand the nature of time or, according to Letheby (2021), myself. If you believe that our experiences just purely come from our brains and molecules doing their thing, then it’s completely uncontroversial that chemicals that change how our brains work will change our experiences.

I’ll talk about more possible ways to solve or resolve the challenge below, but this is one way to make psychedelic experiences compatible with strict naturalism: just categorise them as not being real. If spirits, universal consciousness, oneness with the cosmos, shadow beings, non-duality, DMT entities, etc., are all illusions and we accept them as such, there is no clash with an uncompromising scientific worldview.

On the other hand, if I take my experience to be something more than just pure illusion, that my consciousness went somewhere, or that normal filters of perception were stripped away so I could perceive a more real version of reality, this presents potential challenges for strict naturalism. My belief that I really perceived outside of time and the version of naturalism that says this is impossible can’t both be true.

What do we do? Do we decide our experiences are pure illusion? Or do we discard science? Neither choice seems very appealing. Luckily, there are more (and better) options.

Liberal Naturalism

One way out of this is to be more expansive with what we take to be natural and the reasons for believing something exists. Depending on what area you’re looking to extend, you might come to adopt something like what’s known as Liberal Naturalism.

Liberal Naturalism isn’t precisely defined. Rather, it’s a group of philosophies that argue there are phenomena that can’t be reduced to scientific theories or properly investigated using scientific methods, but that are still real features of the natural world without being supernatural (Raleigh, 2022).

The basic idea is that what we can think and say is real might not only be what today’s currently accepted science says it is. As our understanding of the full breadth of reality grows, some things that science says are illusions or folk myths might turn out to be real. Alternatively, what we take from these experiences might constitute other ways of knowing, which are still valid; they’re just not science.

Under this proposal, you could say that something that strict naturalism ruled out, say, plant spirits or reincarnation, is still real and maybe even potentially discoverable by science. These things just aren’t described by today’s physics, etc., and they might never be.

Is all of this in line with current science? Probably not. Will it make some scientists and philosophers grumpy? Absolutely! But this is a way to make psychedelic experiences compatible with naturalism, without giving away your commitment to good science. All you need to do is admit that everything that exists is natural, but that science is not ‘the last word about what exists and the last word about what is known’ (Macarthur, 2024).

It’s important to understand, though, that Liberal Naturalism doesn’t automatically give you license to believe things that conflict with science. If you think the Earth isn’t round or that the Standard Model of particle physics is wrong, you’d still need to prove it!

Psychedelic Experiences and Scientism

Earlier on, I implied that there were multiple solutions or resolutions to this challenge. That was kind of disingenuous, as they all feature two basic moves: categorise the experiences in ways that don’t present a challenge for naturalism or adjust naturalism itself.

Of course, the biggest adjustment you could make to naturalism would be to discard it on the grounds that it’s just totally wrong. But I’m not sure that I could prove it to be totally worthless. If you make naturalism broad enough, it can accommodate almost anything, except things like a God that isn’t subject to any laws of nature. Even then, philosophers like Spiegel (2019) have tried to carve out a space for ‘near-naturalism’ that allows for such beings to exist.

Nor should we want to discard science. As a method for discovering certain kinds of useful information, systematic empirical observation seems hard to beat. But it doesn’t tell us everything that’s worth knowing, nor every way we can know it. Here are three examples of this:

1. Some important questions are about the ethical or moral value of some action. I can observe the effects of a drug on living things to the point where I can tell you everything about its positive and negative impacts. But that information, by itself, tells us nothing about whether it’s ethical to sell this substance for therapeutic use. Only other moral values, such as physical harm being bad or personal autonomy being good, allow us to make moral judgments on this decision.
2. There are also definitional or analytic truths that we ‘know’ without resorting to observation. Everything from ‘triangles have three sides’ to logical axioms like the principle of non-contradiction is a solid piece of knowledge we cannot verify using science.
3. Finally, there are limits to what we can observe, even using microscopes and telescopes. This is an enormous topic by itself. For now, it’s enough to know that the question of what science can say about the existence (or not) of things we cannot observe is open to philosophical debate.

I mention these things because they help us sketch the limits of science and see when it’s not staying in its lane. If someone tells you that science has proven that ‘capitalism is the best economic system’ or ‘God doesn’t exist’, they’re committing scientism:  treating science as if it were the only true method to acquire knowledge, even where empirical observation is impossible.

Note that this isn’t quite the same claim as naturalism, that only natural (and not supernatural) things exist. Scientism is the view that what is real and what we can know are solely defined by what’s measurable using today’s science. What we see sometimes in this area is people using these terms interchangeably, even though the core claims aren’t identical.

From the perspective of liberal naturalists like Macarthur (2024), Letheby’s very strict naturalism contains a kind of scientism. A more overt example is when Zeus Tipado confidently declares on social media that there’s no such thing as DMT entities. 

Integrating Psychedelics into Naturalism

To (finally) answer the question: yes, psychedelic experiences, if we think they’re more than just illusion, present a challenge to a strict naturalism that sees today’s science as the last word on how reality works.

But for versions of naturalism that don’t treat science as the only valid source of knowledge, the conflict largely disappears. We could still look for scientific explanations for everything we see and experience. If reality turns out to be bigger and weirder than we thought, or if some things are just inherently beyond science’s grasp, we’d be OK. That is the real challenge that naturalism has to integrate. 

Samuel Douglas | Community Blogger at Chemical Collective | theethicaltrip.beehiiv.com/

Samuel is one of our community bloggers here at Chemical Collective. If you’re interested in joining our blogging team and getting paid to write about subjects you’re passionate about, please reach out to Sam via email at samwoolfe@gmail.com